twin 496ho's one surges
06-24-2007, 05:54 PM
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twin 496ho's one surges
what would be the cause and fix starboard motor surges in neutral or in gear you can feel it. the port is fine. it surges about 300 rpms ttou can see it on the tack
06-25-2007, 09:33 AM
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The trouble is that symptom is not specific to any one problem. Could be fuel pressure, clogged/leaking injector, plug, plug wire, coil, TPS, MAP, ect. Do you have a scan tool?
Dave
Dave
06-25-2007, 09:48 AM
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I had a Volvo 8.1GXi do that. I replaced the IAC and ECM per Volvo and it never really completely solved the issue. Real pain when trying to load on the trailer!
I'd start with making sure the IAC is working correctly.
I'd start with making sure the IAC is working correctly.
06-25-2007, 11:11 AM
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Mine would surge like it had a blower on it when it was just off idle.
I sent my ECM into Whipple for the Stage 2 program and put in the low temp thermostat. It runs smooth now without all the shoot on the transom.
I sent my ECM into Whipple for the Stage 2 program and put in the low temp thermostat. It runs smooth now without all the shoot on the transom.
06-25-2007, 12:20 PM
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Sounds like it's sucking hard for fuel. I'd start with pouirng the fuel out of the separators into a jar or glass bowl, let set for awhile, then check it's condition.
Next take the inlet fitting off the boost pump behind your separator (while it's off) and ensure the fine screen is clean. Then while you're at it, pop the injectors out one side at a time, flip over tap out any crud, then spray out with electrical contact cleaner (plastic safe) and reinstall. To top it off, borrow a fuel pressure tester to test the pressure in the rail to ensure the boost pump is working to help supplement the main pump at the cool fuel spot on the port side.
Other possiblilty is one or more injectors have crapped out?
Next take the inlet fitting off the boost pump behind your separator (while it's off) and ensure the fine screen is clean. Then while you're at it, pop the injectors out one side at a time, flip over tap out any crud, then spray out with electrical contact cleaner (plastic safe) and reinstall. To top it off, borrow a fuel pressure tester to test the pressure in the rail to ensure the boost pump is working to help supplement the main pump at the cool fuel spot on the port side.
Other possiblilty is one or more injectors have crapped out?
06-25-2007, 12:44 PM
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the boat only has 52 hours on it could it still be all of the above.I took off the fuel water seperator no water or crud I change them every 20 hours with the oil change.I will try the other things tonight. thank you all
06-25-2007, 12:57 PM
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Forgot to mention the inline filters just prior to the boost pump. They're the automotive inline type, but not very good for the fine particles, only the big junk.
The boost screen and spearators are not that good for thefine stuff that makes it to your injectors. I'm thinking mine got clogged after running the fuel almost out (par for winter storage of Ethanol vice full tanks) allowing for possible manufacturing dust/grit (fiberglass, etc. settled in the tank?) which was small enough to go thru to the injectors.
It's all a process of elimination staritng with the basics before ya start thinking complicated.
The boost screen and spearators are not that good for thefine stuff that makes it to your injectors. I'm thinking mine got clogged after running the fuel almost out (par for winter storage of Ethanol vice full tanks) allowing for possible manufacturing dust/grit (fiberglass, etc. settled in the tank?) which was small enough to go thru to the injectors.
It's all a process of elimination staritng with the basics before ya start thinking complicated.
